JP6020840B2 - Sintering raw material manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a sintered raw material to be used as a raw material for a sintered ore charged into a blast furnace, and specifically relates to a method for producing a sintered raw material using steelmaking slag as a part of the sintered raw material. is there.

Sinter ore, which is a major iron source in the blast furnace ironmaking process, is generally manufactured by the following process. First, powder ore of about 10 mm or less, which is the main raw material, is returned to CaO-based auxiliary materials such as limestone, dolomite, and steelmaking slag as flux sources, SiO _2- based auxiliary materials such as silica and serpentine, and an appropriate amount of water. And then uniformly mixed and granulated to form granulated particles, also called pseudo particles. The granulated raw material is covered with powdered coke or smokeless coal powder as solid fuel (carbon material). And

  Next, the granulated particles are filled as a sintering raw material on a pallet (grate) of a sintering machine to form a sintering raw material charging layer, and then a carbon material (powder coke) contained in the surface layer portion of the charging layer. ), Air is sucked in a wind box arranged below the pallet, oxygen is introduced into the charging layer, the coke is burned, and the sintering heat is used to heat the sintering raw material to a temperature of 1200 ° C. or higher. The resulting sintered cake is pulverized with a crusher or the like disposed on the exit side of the sintering machine, screened with a sieve having an opening of about 5 mm, for example, and +5 mm is sent to the blast furnace as a product. 5 mm is repeatedly used as return ore and used as a raw material for granulated particles.

  The sintered ore produced in this manner is required to be excellent in properties such as cold strength, reducibility, and reduced powderability. Since these characteristics vary greatly depending on the type (origin) of the iron ore to be used, the blending ratio of the auxiliary materials and the amount of coke powder added are appropriately adjusted according to the respective characteristics. In recent years, with the increase in steel production, it has been required to increase the productivity of sintered ore, and to increase the productivity of blast furnaces, higher quality sintered ore is required. It has become to. Therefore, the development of technology for producing high-quality sintered ore with high productivity has become an important issue.

  By the way, the steelmaking slag generated from the steelmaking process at the steelworks includes pretreatment slag generated from the ironmaking preliminary treatment process, decarburization slag (converter slag) generated in the decarburization process such as a converter, and desiliconization process. There are desiliconization slag generated, desulfurization slag generated in the desulfurization process, dephosphorization slag generated in the dephosphorization process, secondary smelting slag generated in the secondary smelting process, and continuous cast slag generated in the continuous casting process. . However, the steelmaking slag has not been effectively reused in the steel field. This is because, for example, decarburized slag may be recycled in the dephosphorization process, but because of its high melting point, it is difficult to use a large amount in a dephosphorization furnace. Therefore, steelmaking slag has been reused mainly in the civil engineering field, and about 40% of the production volume is landfilled or disposed of. However, with the recent strengthening of environmental regulations, the amount of landfill and disposal has gradually decreased. It is also used as a cement raw material, but the amount is very small.

  Therefore, paying attention to the fact that steelmaking slag contains a large amount of CaO, it has been studied to reuse this as a flux in the manufacturing process of sintered ore. For example, Patent Document 1 discloses a technique for improving the quality of sintered ore by mixing a mill scale when converter slag is used as a sintered blending raw material, and Patent Document 2 discloses iron ore having a large number of goethite components. The technique which suppresses the reaction which weakens the intensity | strength of a sintered ore by mixing the converter slag with low reactivity with an iron ore with a stone is disclosed. In addition, Patent Document 3 discloses a technique for use as a flux by increasing the reaction area by increasing the reaction area by reducing the particle size of the converter slag, which is inferior in reactivity with iron ore compared to limestone. Has been. Further, Patent Document 4 is effective in preventing the deterioration of the quality of the sintered ore by selectively combining the hardly sinterable dolomite that causes the quality reduction of the sintered ore with the easily sinterable steelmaking slag. Discloses a technique for recycling steelmaking slag.

However, as shown in Table 1, component composition examples of converter slag and desulfurization slag are shown in comparison with fine ore and the like, steelmaking slag differs greatly in component composition and melting point depending on the type, and desulfurization slag is In addition to CaO, it contains a large amount of Al ₂ O ₃ . Since this Al ₂ O ₃ raises the melting temperature of the melt phase necessary for obtaining the sintered ore and lowers the fluidity, it significantly impedes the productivity of the sintered ore. Moreover, since converter slag has high P and cannot be removed in a blast furnace, there is also a problem that the cost of removing P in steelmaking increases. Therefore, the actual situation is that reusing steelmaking slag as a raw material for sintering is not actively carried out at present.

  Therefore, as a technique for overcoming the above problems, in Patent Document 5, steelmaking slag and sintered raw materials other than steelmaking slag are separated and granulated to an appropriate size and then granulated from steelmaking slag. By mixing the particles uniformly in the granulated particles derived from raw materials other than steelmaking slag and placing them on the pallet of the sintering machine, the harmful effects of the steelmaking slag are contained in the granulated particles derived from the steelmaking slag. Techniques have been proposed that do not adversely affect granulated particles derived from other raw materials.

However, even in the technique disclosed in Patent Document 5, there is still a concern about the deterioration of the quality of the sintered ore. This is because, as described above, steelmaking slag containing a large amount of Al ₂ O ₃ generally has a high melting point. In particular, the converter slag generated in the de-P step and the decarburization step has a melting temperature as high as 1300 ° C. or higher, and has a melting temperature close to the upper limit of the sintering temperature of the sintering process. Therefore, in the sintered raw material charging layer charged on the pallet of the sintering machine, the granulated particles containing the high melting point steelmaking slag are fused with the granulated particles made of raw materials other than the surrounding steelmaking slag. It is not assimilated and tends to remain in the sintered cake. In addition, the air permeability is improved because there are many voids around the granulated particles of coarse steelmaking slag, but due to the lack of melt assimilation, voids remain around the granulated particles of steelmaking slag. The remaining cracks are likely to occur starting from the gap. Therefore, there is a problem that the strength of the product sintered ore is lowered, the yield is lowered, and the productivity is lowered.

JP 59-205421 A JP 05-039553 A Japanese Patent Laid-Open No. 05-061553 Japanese Patent Laid-Open No. 11-229046 JP 2012-117082 A

  The inventors found that when the steel slag having a high melting temperature is used as a part of the raw material of the sinter, the strength of the product sinter decreases (yield decreases), and the productivity is reduced. As a result of examining the measures to solve the problem of lowering, as a result of the granulation particles of steelmaking slag granulated separately from the raw materials other than steelmaking slag, either of the granulation line granulating raw materials other than steelmaking slag At the position, specifically, at any one of positions 1 to 3 of the granulation line shown in FIG. 1, the raw material (fine ore, CaO-based auxiliary material, etc.) adheres or is coated on the surface. And by facilitating melting assimilation with the granulated particles other than the steelmaking slag existing around the granulated particles of the steelmaking slag. The ability to suppress the occurrence of cracks starting from granulated particles Heading, and the technique has been filed as Japanese Patent Application No. 2013-189483.

  However, in order to realize the above technique, when the granulated particles of the steelmaking slag are put into the granulation line of raw materials other than the steelmaking slag, the position 2 in front of the secondary granulator shown in FIG. Or when it is charged at the position 3 in front of the primary granulator, the granulated particles of the steelmaking slag must have a strength that does not break down due to rolling or impact by granulation and do not pulverize. It is. However, the conventional granulated particles of steelmaking slag do not have a strength that can sufficiently withstand rolling in the granulation line. In addition, granulated particles of steelmaking slag may be crushed by its own weight, broken or pulverized when it is loaded with other granulated particles into vibration or dropping when transported by a belt conveyor or the like. high. Therefore, in order to introduce the granulated particles of the steelmaking slag into the granulation line of raw materials other than the steelmaking slag, it is necessary to increase the strength of the granulated particles of the steelmaking slag. As a means for increasing the strength of the granulated particles, there is a method of adding a solidifying agent such as cement, but it is difficult to apply to the production of a sintered raw material.

  The present invention has been made in view of the above-mentioned problems in the prior art, and the purpose thereof is a steelmaking slag having sufficient strength to withstand rolling in a granulation line for granulating raw materials other than steelmaking slag. The purpose of this invention is to propose a method for producing a sintered raw material capable of producing granulated particles easily and inexpensively.

  The inventors have intensively studied to solve the above problems. As a result, as a means for improving the strength of the granulated particles of the steelmaking slag, the lime content (CaO) contained in the steelmaking slag is utilized, the free CaO and water are reacted to generate hydroxide, By curing for a predetermined time and reacting with carbon dioxide in the air, the lime content can be solidified as a carbonate, and the carbonate expands to fill the voids between the particles, thereby increasing the strength of the granulated particles. The inventors have found that this can be enhanced, and have led to the development of the present invention.

That is, the present invention is a raw material of the blast furnace sinter divided into a steelmaking slag and materials other than steel slag, a method for producing a sintered material was granulated, the steelmaking slag is mixed with water, granulated When the granulated particles of the steelmaking slag are put into a granulation line of raw materials other than the steelmaking slag, and the raw materials other than the steelmaking slag are adhered or coated on the surface of the granulated particles of the steelmaking slag Then, a method for producing a sintered raw material is proposed in which the granulated particles of the steelmaking slag are cured and then fed without drying.

  The method for producing a sintered raw material according to the present invention is characterized in that the curing period is 5 days or more.

  In addition, the method for producing a sintered raw material of the present invention is characterized in that when the steel slag is granulated, 20 or less mass% of ore and / or dust is mixed with the steel slag.

A method of manufacturing a sintered material of the present invention, the granulated particles of the steel slag, into the inside 2 Tsugizo granulator from the discharge side of the 2 Tsugizo granulator for granulating lines materials other than steel slag or turning, or position after the front and 1 Tsugizo granulator of the 2 Tsugizo granulator, 1 Tsugizo granulator, and materials other than steel slag at any location before the 1 Tsugizo granulator It is characterized by being put in.

A method of manufacturing a sintered material of the present invention, when introduced therein from the discharge side of the 2 Tsugizo granulator granulated particles of the steel slags, 2 Tsugizo particle flight residence time 10 seconds It is characterized by the above.

  Further, in the method for producing a sintered raw material of the present invention, the granulated particles of the steelmaking slag are charged into raw materials other than the steelmaking slag within a range where the content of the steelmaking slag with respect to the entire sintered ore is 10 mass% or less. It is characterized by that.

  According to the present invention, since the strength of the granulated particles of the steelmaking slag can be significantly improved, even if the granulated particles of the steelmaking slag are put into a granulation line of raw materials other than the steelmaking slag, Even if the granulated particles are transported or charged into a sintering machine, the collapse and pulverization of the granulated particles of the steelmaking slag can be suppressed. And the sintering time can be shortened. Furthermore, the granulated particles obtained by putting the granulated particles of the above steelmaking slag into the granulation line of raw materials other than steelmaking slag are adhered and coated with ungranulated powder ore, limestone, powder coke, etc. Therefore, at the time of sintering, melting assimilation with granulated particles other than steelmaking slag existing around it is promoted, so high strength sintered ore is produced with high yield and high productivity. It becomes possible.

In a prior art, it is a figure explaining the position which puts the granulated particle of steelmaking slag into the granulation line of raw materials other than steelmaking slag. It is a figure explaining the experimental method which investigates the influence of the curing period on the crushing strength of the granulated particle of steelmaking slag. It is a graph which shows the influence of raw materials other than steelmaking slag, and the curing period which influences the crushing strength of the granulated particle of steelmaking slag. It is a figure explaining the example of a method of curing steelmaking slag. It is a figure explaining the manufacturing method of the sintering raw material of this invention.

As described above, the inventors have made it possible to easily and inexpensively produce granulated particles of steelmaking slag having sufficient strength to withstand rolling and impact in a granulation line of raw materials other than steelmaking slag, We examined the policy repeatedly. As a result, utilizing the lime (free CaO) contained in the steelmaking slag, the free CaO and water are reacted, and the following formula:
CaO + H ₂ O → Ca (OH) ₂
To generate a hydroxide, and to react the hydroxide with carbon dioxide in the air,
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O
It was found that the strength of the granulated particles can be increased by expanding the carbonate while simultaneously forming and solidifying the carbonate. Hereinafter, this effect is referred to as “self-hardening effect” of the steelmaking slag.

  However, it takes time for free CaO contained in the granulated particles immediately after granulation to react with moisture. Further, it takes time for the hydroxide to absorb and react with carbon dioxide in the air. Therefore, the inventors maintain the wet state for a long time without drying the granulated particles of the steelmaking slag, so-called curing, the time for forming the hydroxide, and the hydroxide It came to the idea that sufficient time was required for carbonation.

Hereinafter, a basic experiment for confirming the above idea will be described.
As shown in FIG. 2, the raw material (granulated raw material) of the granulated particles of steelmaking slag is put into a stirrer, granulated water is added so that the water content becomes 19 mass%, and after stirring and mixing for 180 seconds Furthermore, it was granulated with a drum mixer for 60 seconds to obtain pseudo particles (granulated particles) having a particle size of 3.0 to 7.7 mm. Under the present circumstances, the granulation raw material thrown into a stirrer was made into the following three conditions.
Condition A: Steelmaking slag 100 mass%
Condition B: Steelmaking slag 80 mass% + iron ore 20 mass%
Condition C: Steelmaking slag 80 mass% + dust 20 mass%
Here, a steelmaking slag (decarburization furnace slag) having a melting temperature of 1500 ° C. is used for the steelmaking slag, a pellet feed (particle size of 150 μm or less) that is fine ore is used for iron ore, and converter dust is used for dust. Using.

  Next, the granulated particles obtained as described above are piled up in a yard without drying, and covered with a waterproof sheet to prevent drying, and the curing period is 0 days, 5 days, 10 days and The crushing strength of the granulated particles after 20 days was measured according to JIS M8718.

The measurement results are shown in FIG. From this figure, under the condition A where the steelmaking slag is 100 mass%, when the curing period is 0 days, the crushing strength is 4.4 kg / piece, but after the 5 days curing, it is 40.1 kg / piece for 10 days. It increased to 61.9 kg / piece after curing and 72.3 kg / piece after 20 days curing.
Moreover, in condition B which mix | blended 20 mass% of iron ore with steelmaking slag 80mass%, when a curing period is 0 day, crushing strength is 2.1 kg / piece, but after 5 days curing, it is 12.4 kg / piece. After curing for 10 days, it has increased to 18.2 kg / piece, and after curing for 20 days, it has increased to 15.0 kg / piece.
Moreover, in the condition C which mix | blended 20 mass% of dust with steelmaking slag 80mass%, when a curing period is 0 days, crushing strength is 3.0 kg / piece, but after 5 days curing, 15.8 kg / piece, After the 10-day curing, it has increased to 12.2 kg / piece, and after the 20-day curing, it has increased to 29.9 kg / piece.
From the above experimental results, it was confirmed that the granulated particles of the steelmaking slag can be remarkably improved in strength by being cured without being dried after granulation.

  Here, the above-mentioned “curing without drying after granulation” means that it is sufficient to pile up steelmaking slag in the yard and prevent sun drying, for example, as shown in FIG. As shown in Fig. 4 (b), it can be realized by stacking 10 tons or more in the yard and covering it with a waterproof sheet to prevent drying. It can also be realized by storing it in In this case, the surface layer is dried, but by storing it in units of 10 tons or several tens of tons, the inside can be kept in a water-containing state, so that it can be cured.

  Therefore, in the present invention, when using steelmaking slag as a part of the raw material of the sintered ore, as shown in FIG. 1, the granulated particles of the steelmaking slag are put into the granulation line of the raw materials other than the steelmaking slag, and the above When attaching or coating raw materials other than steelmaking slag on the surface of the granulated particles of steelmaking slag, as shown in FIG. 5, the steelmaking slag is granulated into granulated particles, and then dried for a predetermined period without drying. It was decided to apply after curing in a wet state.

  In addition, according to this invention, since the intensity | strength of granulated particle can be raised significantly by the self-hardening effect of steelmaking slag, iron ore, such as pellet feed (particle size of 150 micrometers or less) which is a fine powder ore, is added to the said steelmaking slag. (Powder ore) and dust containing a lot of iron generated at steelworks, for example, blast furnace ash generated from the blast furnace process, converter dust generated from the steel making process, and difficult granulation such as mill scale generated from the hot rolling process Can be mixed with powder raw materials. However, since a large amount of mixing impairs the self-hardening effect of the steel slag, it is preferable to limit the blending ratio in the case of mixing to 20 mass% or less. More preferably, it is 10 mass% or less.

  Moreover, it is preferable that the curing period required in order to express the self-hardening effect of the said steelmaking slag is 5 days or more so that FIG. 3 may show. However, when iron ore or dust is mixed with steelmaking slag, it is preferably 10 days or more, more preferably 15 days or more, and even more preferably 20 days or more.

  Steelmaking slag that can be used in the present invention includes blast furnace ash, converter dust, pellet feed, etc., in addition to desulfurization slag and converter slag generated in the hot metal pretreatment. Further, since it contains iron, it can be used as a raw material for sintering, but a powder raw material that is considered to be difficult to granulate can also be used.

  Moreover, although the quantity of granulated water required when granulating steelmaking slag changes with kinds of steelmaking slag, it is preferable to set it as 19 mass% or more and 23 mass% or less in general.

  Moreover, since the granulated particles of the steelmaking slag of the present invention have high strength as shown in FIG. 3, the steelmaking slag is put into a granulation line of raw materials other than the steelmaking slag, and the surface of the granulated particles of the steelmaking slag is made of steel. Raw materials other than slag, specifically, ungranulated powder ore, CaO-based auxiliary materials, and the like can be attached or coated. As a result, the surface of the granulated particles of the steelmaking slag has a low melting point, it is easy to form a molten layer during sintering, and melting assimilation with the granulated particles made of raw materials other than the steelmaking slag existing around is promoted. Therefore, the generation of cracks starting from the granulated particles of steelmaking slag is suppressed, the strength and yield of the product sintered ore are improved, and the productivity can be increased.

Here, the position where the granulated particles of the steelmaking slag are put into the granulation line of the raw material other than the steelmaking slag is such that the granulation line of the raw material other than the steelmaking slag is added to the powder ore which is the main raw material and the CaO-based auxiliary material In the case of being composed of a primary granulator that mixes and agitates and uniformly mixes and granulates, and a secondary granulator that granulates the mixed raw materials into pseudo particles (granulated particles) Is inserted into the secondary granulator from the discharge side or the position before the secondary granulator and after the primary granulator, the primary granulator, and the primary granulator It is preferable to be in any position before the granulator. Moreover, when it is comprised only with a primary granulator, it will throw in into the inside from the discharge part side of a primary granulator, or in any position before a primary granulator, except steelmaking slag It is preferable to put in the raw material.

However, when the strength of the granulated particles of the steelmaking slag is relatively weak, from the viewpoint of preventing the granulated particles from collapsing and pulverizing due to rolling in the granulator, etc., downstream of the granulation line. It is preferable to feed in the inside (position 1 shown in FIG. 5) from the side of the outlet of the secondary granulator located. In this case, from the viewpoint of coating the ungranulated raw materials such as more than the minimum required on the surface of the granulated particles of steel slag, the residence time to be discharged after charged into the inner portion of the 2 Tsugizo granulator It is preferable to secure 10 seconds or more. A more preferable residence time is 15 seconds or more.

  On the other hand, when the granulated particles of the steelmaking slag have a strength that does not cause collapse due to rolling in the secondary granulator, the position before the secondary granulator and after the primary granulator (see FIG. 5 may be put into a raw material other than steelmaking slag. Further, when the strength of the granulated particles of the steelmaking slag is higher, the primary granulator or the front of the primary granulator (position 3 shown in FIG. 5), that is, a CaO-based auxiliary material, etc. At the same time as the addition of, slag may be introduced into raw materials other than steelmaking slag.

  When the granulated particles of the steelmaking slag are introduced on the upstream side of such a granulation line, more ungranulated raw materials and auxiliary raw materials can adhere to the surface of the granulated particles. In addition, the granulated particles of the steelmaking slag that has been input serve as a nucleus, and the surface thereof is coated with ungranulated raw materials and auxiliary raw materials, so that larger granulated particles can be formed. As a result, the air permeability when charged in the sintering machine is improved and the productivity is improved. In addition, the raw assemblage of raw material and auxiliary raw material that adheres or covers the surface of the granulated particles of steelmaking slag promotes the fusion assimilation with the granulated particles of raw materials other than steelmaking slag during sintering. The strength of the sintered ore can be further increased. However, if granulated particles that are larger than the granulated particle size of the sintered raw material that does not contain steelmaking slag are formed, the sintering reaction becomes non-uniform and the strength of the product sintered ore may be reduced. It is desirable to determine the loading position in consideration of the balance between productivity and yield.

  In addition, in the manufacturing method of the sintering raw material of this invention, it is preferable to throw in the granulated particle | grains of the said steelmaking slag within the range from which the ratio of steelmaking slag with respect to the whole sintered ore exceeds 0 mass% and is 10 mass% or less. If it exceeds 10 mass%, the negative effects of steelmaking slag will become obvious, and the strength of the sintered ore will be reduced. In addition, it is necessary to reduce the amount of auxiliary limestone added to adjust the components (basicity) of the sintered ore. As a result, the sintering reactivity is significantly reduced, making it difficult to maintain productivity, and the impurities contained in the steelmaking slag increase the impurity element concentration in the hot metal, which is acceptable as hot metal. This is because the range may be exceeded. Preferably it is 6 mass% or less.

As in the basic experiment described above, steelmaking slag was put into a stirrer, granulated water was added so that the water content was 19 mass%, stirred and mixed for 180 seconds, and further granulated with a drum mixer for 60 seconds. Pseudo particles (granulated particles) having a particle size of 3.0 to 7.7 mm were used. Under the present circumstances, the granulation raw material thrown into a stirrer was made into the following three conditions.
Condition A: Steelmaking slag 100 mass%
Condition B: Steelmaking slag 80 mass% + iron ore 20 mass%
Condition C: Steelmaking slag 80 mass% + dust 20 mass%
Here, a decarburization furnace slag having a melting temperature of 1500 ° C. was used for the steelmaking slag, pellet feed was used for iron ore, and converter dust was used for dust.
Next, the granulated particles of the conditions A to C obtained as described above were piled up in a yard without being dried, covered with a waterproof sheet, and cured for 5 days.
Next, the granulated particles of the steelmaking slag cured as described above are put into a granulation line of raw materials other than the steelmaking slag at the position 1 shown in FIG. Granulated particles were obtained by adhering or covering granulated powder ore, limestone, and powdered coke. At this time, the residence time in the secondary granulator was 30 seconds.
In any of the above conditions, the mixing ratio of the steelmaking slag with respect to the entire sintered raw material was 3.4 mass%. Addition of the auxiliary raw material and coke breeze in the secondary granulator is input at a position where the residence time until the discharge of the secondary granulator is 30 seconds in any condition, and the input amount of the auxiliary raw material at this time Was adjusted so that the basicity (CaO / SiO ₂ ) of the entire sintered raw material was 2.0, and the amount of powder coke added to the entire sintered raw material was 4.8 mass%.

Next, a sintering experiment was performed using the three types of granulated particles obtained as described above as sintering raw materials.
In the above-mentioned sintering experiment, after filling the sintering raw material so that the layer thickness is 400 mm in a test pan having an inner diameter of 300 mmφ × height of 400 mm in the size of the raw material charging portion, The coke was ignited, sucked from below the pan at -700 mmAq, and air was introduced into the packed bed to combust the powder coke. Under the present circumstances, the time required for sintering of each sintering raw material, the yield and cold strength (SI) of the obtained sintered ore were measured according to JIS M8711, and the production rate (unit hearth area (m ² ) and the sinter production (t) per unit time (hr).
In the sintering experiment, as base conditions (reference examples), in addition to the sintering raw materials obtained from the above conditions A to C, granulated particles (condition D) which do not contain any steelmaking slag and are not cured. The sintering experiment used for the sintering raw material and the sintering experiment (comparative example) used for the sintering raw material without curing the sintering raw material obtained from the above conditions A to C (0 day) were also carried out.

  The results of the above sintering experiment are shown in Table 2. From this result, after granulation, the granulated particles obtained by putting the granulated particles of steelmaking slag which has been cured for 5 days to increase the strength into the granulation line of raw materials other than steelmaking slag are used as the sintering raw material. Compared with the case where the granulated particles of steelmaking slag that is not cured are put into the granulation line of raw materials other than steelmaking slag, the sintering time is shortened, and the strength of the product sintered ore, It can be seen that the yield can be improved and the production rate is greatly improved. This is because the strength of the granulated particles of the steelmaking slag is improved by curing, the collapse and pulverization of the steelmaking slag is suppressed, the air permeability is improved, and the granulated particles of the steelmaking slag are other than the steelmaking slag. Is put into the granulation line of the raw material, and the surface of the granulated particles adheres or covers ungranulated raw materials (such as fine ore and CaO-based auxiliary materials), and the surface of the granulated particles of the steelmaking slag is low. Melting point makes it easy to form a molten layer, promotes melting assimilation with ore structure formed from granulated particles of raw materials other than steelmaking slag mixed around during sintering, and improves strength and yield of product sintered ore This is probably due to the fact that

  In the above description, a method for producing sintered ore using a solid fuel (powder coke) as a sintering heat source has been described. However, the technology of the present invention is not limited to the above example, and for example, a solid The present invention can also be applied to a sintering raw material of a method for producing a sintered ore by supplying a gaseous fuel in addition to a system fuel and / or a method for producing a sintered ore by adding oxygen.

Claims (6)

The material of the blast furnace sinter divided into a steelmaking slag and materials other than steel slag, a method for producing a sintered material by granulation,
After steelmaking slag is mixed with water and granulated to form granulated particles, the granulated particles of the steelmaking slag are put into a granulation line of raw materials other than the steelmaking slag, and are put on the surface of the granulated particles of the steelmaking slag. A method for producing a sintered raw material, characterized in that when a raw material other than steelmaking slag is adhered or coated, the granulated particles of the steelmaking slag are cured without being dried and then charged. The method for producing a sintered raw material according to claim 1, wherein the curing period is 5 days or more. 3. The method for producing a sintered raw material according to claim 1, wherein when the steel slag is granulated, 20 mass% or less of fine ore and / or dust is mixed with the steel slag. The granulated particles of the steel slag, or introduced from the discharge side of the 2 Tsugizo granulator for granulating lines materials other than steel slag to the inside 2 Tsugizo granulator, and prior to the 2 Tsugizo granulator It puts into raw materials other than steelmaking slag in the position after a primary granulator, or a primary granulator, and the position in front of a primary granulator, respectively. 4. The method for producing a sintered raw material according to any one of 3 above. When introduced therein from the discharge side of the 2 Tsugizo granulator granulated particles of the steel slags according to claim 1 to 4 for 2 Tsugizo particle flight residence time, characterized in that at least 10 seconds The manufacturing method of the sintering raw material of any one of these. The granulated particles of the steelmaking slag are charged into a raw material other than the steelmaking slag within a range where the content of the steelmaking slag with respect to the entire sintered ore is 10 mass% or less. 2. A method for producing a sintered raw material according to item 1.

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